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Journal of Materials Science

, Volume 51, Issue 3, pp 1437–1444 | Cite as

The effect of elevated temperature and high moisture content on the fracture behaviour of thermally modified spruce

  • Pekka TukiainenEmail author
  • Mark Hughes
Original Paper

Abstract

The aim of the present study was to investigate the effect of moisture content and temperature on the fracture behaviour of thermally modified Norway spruce (Picea abies [L.] Karst.) in the transverse plane. Spruce was thermally modified at two heat treatment temperatures, 190 and 210 °C. Mode I fracture tests were carried out at temperatures of 22 and 50 °C on air-dried and fully water-saturated (>fibre saturation point) material. Small CT specimens were used, and load–CMOD curves were recorded. Characteristic fracture parameters were calculated. The fracture surfaces were subsequently examined using optical microscopy. Thermal modification altered all the calculated fracture parameter values and the changes increased as the severity of heat treatment increased. The parameters were altered more in the radial-tangential (RT) than in tangential-radial (TR) orientation. The failure mode changed due to heat treatment in the TR orientation but in the RT orientation the failure mode of unmodified and heat treated material differs only at high moisture content and elevated temperature.

Keywords

Failure Mode Middle Lamella Thermal Modification Early Wood Unstable Crack Propagation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This work formed part of “E-Wood”, a project supported by the Multidisciplinary Institute of Digitalisation and Energy (MIDE, http://www.mide.aalto.fi). The authors would like to thank Raute Oyj for providing fresh spruce.

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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Department of Forest Products Technology, School of Chemical TechnologyAalto UniversityAaltoFinland

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